Pattern cam selecting mechanism for zigzag sewing machines



M R. PERLA Dec. 10, 1963 PATTERN CAM SELECTING MECHANISM FOR ZIGZAG SEWING MACHINES 2 Sheets-Sheet 1 Filed Dec. 5, 1960 3 Mom Nm 8 m....

WITNESS fla QM M R. PERLA Dec. 10, 1963 PATTERN CAM SELECTING MECHANISM FOR ZIGZAG SEWING MACHINES Filed Dec. 5, 1960 2 Sheets-Sheet 2 INVENTOR Martin R. Perla WITNESS z/zdw W 3,113,538 PATTERN CAM SELECTENG MECHANISM FGR ZIGZAG EWHNG MAtlHlNES Martin R. Perla, Fair-field, Conn, assignor to The Singer Company, a corporation of New Jersey Filed Dec. 5, 1969, Ser. No. 73,673 1 Claim. (Cl. 112-15S) This invention relates to zigzag sewing machines, and more particularly to a sewing machine having a plurality of stitch pattern controlling means such as a stack of pattern cams or the like and operator influenced means for selectively rendering one or more of the stitch pattern controlling means effective.

It is an object of this invention to provide a novel operator-influenced push button device for selectively rendering effective one or more of the stitch pattern controlling means of a zigzag sewing machine.

Another object of this invention is to provide a push button operated cam selector for a zigzag sewing machine which is conveniently assembled in a removable cover plate for the sewing machine casing and thus may be readily sub-assembled for use with either new or existing machines in the field.

In order that the invention may be clearly understood and readily carried into effect, mechanism in accordance therewith will now be described by way of example with references to the accompanying drawings in which:

FIG. 1 represents a side elevational view of a sewing machine having this invention applied thereto With portions of the bracket arm broken away and illustrated in vertical cross-section,

FIG. 2 represents an enlarged top plan view of a portion of the sewing machine of FIG. 1 with the top cover plate and the sewing machine pattern cam follower throwout bar removed, and

FIG. 3 represents an enlarged bottom plan view of the top cover plate of the sewing machine of FIG. 1 with the push button supporting plate removed therefrom, and including a fragment of the sewing machine pattern cam follower frame illustrating the relationship of the sewing machine pattern cam followers with the throwout bar.

In the drawings, FIG. 1 illustrates a zigzag sewing machine having a pattern cam controlled needle jogging mechanism of the type disclosed in the United States Perla et :11. Patent No. 2,756,703, July 31, 1956, and including a plurality of pattern cams and selectively effective pattern cam followers of the type disclosed in the United States Perla Patent No. 2,810,360, October 22, 1957, to which patents reference may be had for a detailed description thereof. The present invention, however, will be understood by those skilled in the art in the light of the following brief description of the sewing machine and needle jogging mechanism.

Indicated at 11 in the drawings is the hollow bracket arm of a sewing machine casing, which bracket arm is open at the top and adapted to be closed by a top cover plate 12 secured to the bracket 'arm by fastening screws 13. lournaled in bearings 14 and 15 in the bracket arm is a main shaft 16 fitted at one extremity with a balance wheel driving pulley 17. At the opposite extremity the main shaft carries a counterbalance 18 in which is secured a compound crank 19 embraced by a needle thread take-up lever 2i? and by a needle bar driving link 21. The needle bar driving link 21 pivotally embraces a stud 22 fixed on a needle bar 23 journaled in a needle bar gate 24 which is fulcrumed, as at 25, to a supporting member 25 carried in the bracket arm.

A cam shaft journaled transversely of the main shaft 16 in the bracket arm 11 carries a worm wheel 31 in mesh with a worm 32 fastened on the main shaft. Secured for rotation with the cam shaft and disposed within the bracket arm is a stack of pattern cam disks 33, any one or combination of which may be rendered effective to control the pattern of zigzag stitches to be produced by the sewing machine. In addition, the cam shaft 36), exteriorly of the bracket arm, is formed with a flange 34 carrying a locking pin 35 adapted to accommodate an exchangeable pattern cam disk 36 for rotation with the cam shaft. A knurled nut 37 threaded on the free extremity of the cam shaft serves to secure the exchangeable pattern cam 36 on the cam shaft against the flange 34.

A pattern cam follower frame 46 fulcrumed at il in the bracket arm, carries a pivot pin 42 on which is journaled a plurality of pattern cam follower levers one for each of the disks in the stack of pattern cam disks 3-3. Each of the cam follower levers is formed with an operating arm 44, with a cam follower finger 45, and with a pair of detents 46 cooperating with a spring loaded plunger 47 in the frame 4!) for releasably sustaining the cam follower levers either in a position in which the cam follower finger is disposed to track its respective pattern cam disk or in a position in which the cam follower finger is turned out of engagement with its respective pattern cam disk. Also journaled in the frame 4% is a rock shaft 48 having secured thereto at one extremity a rock arm formed with a cam follower finger 49 disposed radially opposite the exchangeable pattern cam disk 36 and at the opposite extremity with an operating rock arm 5i).

The cam follower frame 48 is influenced by a spring means 51 to urge the cam follower fingers 45, as toward the pattern cam disks 33, 36 and is formed with a depending arm 52 pivotally connected by means of a link 53 to a needle bar jogging pitman 54. The pitman 54 extends along the bracket arm and is pivoted as at 55 to one arm 56 of a bell crank fulcrumed in the bracket arm at 57. A bifurcated arm 58 of the bell crank embraces a slide block 59 pivotally secured to an extension 60 of the needle bar gate 24.

Oscillation of the pitman 54 about the pivot 55 in response to cam influenced motion of the frame 40 is constrained to produce longitudinal needle bar jogging motion of the pitman by means of a slide block 7h pivotally secured to the pitrnau and slidably arranged in a slotted guide member 71 carried by the bracket arm Ill. The guide member 71 is angularly adjustable in response to movement of an operator influenced handle 72 at the front of the bracket arm to control the width or bight of the zigzag stitch pattern. The guide member 71 is also displaceable bodily relatively to the bracket arm in response to movement of an operator influenced handle 73 to control the field or neutral position of the zigzag pattern of stitches either to the right, left or centrally of the pattern of zigzag stitches.

In the present invention, the operating arms 44- and 50 of the pattern cam follower fingers are not influenced directly by the machine operator but rather by a plurality of push buttons secured each on a rod 81 slidable loosely in an apertured flange S2 of a support plate 83 secured spanning the open top of the bracket arm 11. Each of the rods 81 is pivoted, as at 84 to one arm of a respective bell crank 85, to the other arm of which is secured by means of a clamp screw 86 a flexible connection 87 secured to one of the operating arms id5il of the cam follower fingers 45-4$. The flexible connections 87 may be of cord, flexible metallic wire, or of synthetic plastic material such as nylon or the like.

The bell cranks are each fulcrtumed on the support plate 83 by means of shouldered screws 88, and preferably the position of each fulcrum screw 88 relatively to the flange 32 on the support plate is different and the rods 81. of correspondingly different lengths so as to provide for substantially parallel spacing of the flexible connections 37 to avoid interference therebetween.

it will be noted with reference to FIG. 1, that each of the flexible connections 87 is arranged to extend from the: operating arms 44-59 in a direction substantially parallel to the radius line xx of the cam follower fingers 45-49 with respect to the fulcrum 41 of the cam follower frame: 4%. With this arrangement, the motion of the cam follower frame in response to tracking of any of the pattern cams by the cam follower fingers 45, 49 will occur in a direction substantially perpendicular to the flexible con-- nc-c-tions 87 and thus give rise to no appreciable interference therebetween.

Upon depression of any one or any combination of the: push buttons 80 the corresponding operating arms 44-56 will be shifted to the left as viewed in the drawings to shift the corresponding cam follower fingers 45-49 into operative position tracking their respective pattern cam disks.

To return the push buttons and all of the cam followers to inoperative position so that a new selection of stitch patterns may be made, a clearing bar 913* is slidably constrained in the top cover plate of the sewing machine bracket arm. The bar 90 is preferably constrained in guide slots formed in spaced reinforcing ribs 91 formed in the top cover and sustained in the guide slots by keeper plates 92 secured by screws 93 to the reinforcing ribs. T he clearing bar 90 is formed with a laterally extending cross head 94 disposed for engagement with all of the operating arms 4450 adjacent to their upper ends to shift each of the cam follower fingers out of operative pattern cam engagement upon movement of the clearing bar to the right, as viewed in FIGS. 1 and 2. A finger grip 95 is preferably secured to the clearing bar and arranged to project upwardly through a slot in the top cover plate for shifting of the bar. The bar is returned automatically by a spring 96 connected to the clearing bar and to the top cover. Movement to inoperative position of the operating arms 44--50 of the pattern cam follower levers will effect, by way of the connections 37 and the bell cranks 85, an outward shift of each of the push buttons 30 which had previously been depressed, and the mechanism will be in readiness for a fresh stitch pattern selection by the operator.

Having thus set forth the nature of this invention, what I claim herein is:

In a zigzag sewing machine having a frame including a hollow upwardly open bracket arm, a top cover plate closing said bracket arm, a drive shaft journaled lengthwise in said bracket arm, a needle bar reciprocated endwise by said drive shaft and supported in said bracket arm for lateral jogging movement, and needle bar jogging mechanism including a plurality of coaxial pattern cams carried in said bracket arm on an axis transverse to said drive shaft, means on said drive shaft for turning said pattern cams, a cam follower frame fulcrumed in said bracket arm on an axis transversely of said drive shaft and overhanging said pattern cams, a plurality of similarly shaped pattern cam follower levers pivoted coaxially on said cam follower frame, each of said cam follower levers having a cam follower finger disposed for movement into and out of tracking engagement with a respective one of said pattern cams upon turning of said cam follower lever relatively to said cam follower frame, means operatively connecting said cam follower frame to said needle bar to jog said needle bar laterally, operator influenced means for turning a selected one or more of said cam follower levers to shift the cam follower fingers thereon into tracking engagement with said respective pattern cams comprising, a push button supporting plate secured to said bracket arm between said bracket arm and said top cover plate, an upturned flange formed on said supporting plate, a plurality of push buttons one for each of said cam follower levers slidably constrained in said support plate flange, a plurality of hell cranks fulcrumed on said support plate, means operatively connecting said push button each to a respective one of said bell cranks, a flexible connection element operatively connected to each bell crank and to a respective one of said cam follower levers to shift said cam follower fingers into tracking engagement with said pattern cams upon depression of said respective push buttons, said connection elements each being disposed substantially parallel to an imaginary plane interconnecting said fulcrum of said cam follower frame and the point of tracking engagement between one of said cam follower fingers and a respective one of said pattern cams, and means for simultaneously retracting said push buttons and shifting said cam follower fingers out of tracking engagement with said pattern cams comprising a bar sli-dably supported in said top cover plate for movement lengthwise of said arm shaft, a cross head formed on said slide bar and disposed abutting said cam follower levers, spring means biasing said slide bar cross head away from said cam follower lever, and operator influenced means for shifting said slide bar cross head into engagement with said cam follower levers to shift said cam follower fingers out of tracking engagement with said pattern cams.

References Cited in the file of this patent UNITED STATES PATENTS 1,464,962 Woodward Aug. 14, 1923 2,840,360 Perla Oct. 22, 1957 3,033,138 B0110 May 8, 1962 FOREIGN PATENTS 219,620 Australia Jan. 14, 1959 1,221,351 France June 11, 1960 1,070,000 Germany Nov. 26, -9 329,688 Switzerland June 30, 1958 

